As far as i understand it, the way you described it they sounded like ghouls. Whilst all tokens remain on the board and can be redeployed if more than 1 is lost from attack, the race itself annoy attack, just keep more tokens in decline.
Is this clear?

Tomb is a watered down version of ghouls. You keep all the tokens you had when you declined the race, redeploying on your decline turn. After that you are only allowed to redeploy if you are attacked, and only to redeploy the leftover tokens from a conquest as if the tomb race was an active race.

Tomb does NOT let your in decline race conquer like ghouls, and you can't choose to redeploy the tomb race any way you like on following turns.